Many members of this forum on both sides of the issue place much greater importance on gay issues than the general public. In reality, the repeal of DADT ranks very low on most Americans' list of priorities. Blocking repeal simply doesn't have the negative political effects that many Atlasians think it does.
The amount of time it would take if people really wanted to repeal it would be a matter of days or hours. It's not like repealing DADT takes 6 months of constant work and focus. It's only been this difficult because people refuse to cooperate and make excuses.
I seriously doubt minority rights will ever be very high on "most Americans' list of priorities." It doesn't mean that ignoring such a thing is the right thing to do, especially with such large public support for DADT's repeal.
To my knowledge, a simple repeal of DADT hasn't been introduced in the recent past. I'm talking a one-issue bill that deals just with 10 U.S.C. § 654.
I suspect Democrats are too scared to introduce it as it's own thing (at least up to this point) for the fear that it will go down even on it's own, basically sealing the deal for it to not pass for the significant future, or that Republicans will complain that there are more pressing matters to deal with, and Democrats get blamed for wasting time.
Even if it was a standalone piece of legislation, as optimistic as I respect you for being, you must know Republicans would still make some sort of excuse to oppose it's repeal. I don't imagine how it would do significantly better as a standalone bill in regard to the Republican vote than it is now.